Abstract

We optically pump water through micrometer thin ice sheets. The ice is locally moved with speeds exceeding 5 cm/s by repetitive melting and freezing, which occurs around a moving infrared laser spot. The minimal channel width is . The diffusion limitation of ice allows for fast spatial biomolecule control without predefined channels, valves, or external pumps. Dye molecules are pumped across an ice-ice interface, showing the possibility of microfluidic applications. Pumping in ice is three orders of magnitude faster than the previously shown for thermoviscous pumping in water.

Received 04 December 2008Accepted 14 February 2009Published online 16 March 2009

Acknowledgments:

We thank Ann Fornof for reading the manuscript. The research was funded by the Emmy Noether program of the Deutsche Forschungsgemeinschaft (DFG), the LMU Innovativ Initiative Functional NanoSystems (FUNS), and the Excellence Cluster NanoSystems Initiative Munich (NIM).